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What is CLAM

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ontap-9
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Applies to

  • ONTAP 9
  • Connectivity, Liveness, Availability Monitor (CLAM)

Answer

Connectivity, Liveness, Availability Monitor (CLAM), is a feature of ONTAP used to monitor connectivity and state of all nodes in the cluster, alert admins of changes, and possibly, take action by takeover.

  • CLAM monitors all nodes in the cluster and determines for each:
    • Administrative state (enabled/disabled)
    • Operation state (connected, live, available)
    • HA takeover status
    • Cluster quorum status
  • CLAM alerts admins about manual actions such as:
    • Node reboot
    • Node takeover
    • Node shutdown

Note: Except for the node the action was one, each node in the cluster will send a Node Out of Quorum AutoSupport message.

  • CLAM alerts admins about unexpected state changes:
    • Power loss
    • Cluster network connection loss
    • Other node unresponsive events

Note: Except for the node with the issue, each node in the cluster will send a Node Out of Quorum AutoSupport message.

  • When CLAM determines a node is not responding (out of quorum), it will:
    • Send a Node Out of Quorum AutoSupport message from each available node in the cluster.
    • Initiate an HA takeover of the node if it continues failing to respond.
    • Generate a memory dump of the node targeted for takeover.
    • The target node will generate a message similar to:

PANIC: Received PANIC packet from partner, receiving message is (Coredump and takeover initiated because Connectivity, Liveliness and Availability Monitor (CLAM) has determined this node is out of quorum.) 

  • Clam monitoring and takeover is enabled by default on:
    • All systems using ONTAP 9.8 and later.
    • SAN enabled systems using ONTAP 9.7 and earlier.

Additional Information

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